Mycoremediation of Synthetic Dyes: An Insight into the Mechanism, Process Optimization and Reactor Design - Microbial Degradation of Synthetic Dyes in Wastewaters - page 18

Fig. 7 Bioreactor designs: continuous stirred-tank reactor a; Expanded Bed and Packed Bed
b and Airlift bioreactors c (Mishra and Malik 2013 )

Recently, researchers have also attempted the immobilization of puri ed enzymes

to carry out the degradation process, such as the immobilization of laccase enzyme
obtained from Myceliophthora thermophila on Eupergit support in a packed bed
bioreactor (Lloret et al. 2012 ).
Other than basic designs, sequential reactor con

gurations, employing anaerobic
and aerobic conditions, have also been proposed by many researchers. Zee and
Villaverde ( 2005 ), Khehra et al. ( 2006 ) have proposed the sequential bioreactors
based on initial anaerobic treatment, followed by aerobic treatment, where the nal

degradation of the products of anaerobic cleavage occurs. However, carcinogenic
aromatic amines, produced during the anaerobic degradation of azo dyes, are not
effectively removed in the subsequent aerobic step, thus limiting the use of this type
of sequential treatment (Mohanty et al. 2006 ). Reverse of this treatment process i.e.
the aerobic degradation, followed by anaerobic treatment, has been proposed by
Novotn

et al. ( 2011 ) for wastewater containing high concentration of dye and
organics. Aerobic step based on theenzymatic degradation by fungi Irpex lacteus in
a fungal trickling

ý

lter (FTF) bioreactor, followed by anaerobic degradation in
bacterial reactors, resulted in ef cient decolorization in rst step and marked TOC